Airbox modding

[tony.mon]

Yep, it works perfectly well, with one suggestion- use clear hose. You will be able to see any emulsion that builds up if you ride in wet weather.
To combat this, I cut a clear lid from an aerosol can to fit over the filter and keep it from road spray.

Ideally you fit a catch tank tee piece at the lowest point, but that's probably overkill.

However, you won't get a sudden increase in power; it just makes cleaning up the pipework from the airbox possible, and means that you can regain the corners, as you don't need corner filters.
Just wrap a section of air filter foam over the stubs and clip them on with a cable tie, and the job is a good one, matey.

As to mine- I've been working on it every night this week- should be done by the weekend, I hope. I had to cut and re-glass some sections to allow the tank to sit down far enough- I may have got a bit greedy in trying to maximise the volume...
Funnily enough it doesn't look anywhere near as big once you get the carbs in.....
When it's ready for final assembly I'll do a series of build pix.

[NZSpokes]

Yep, it works perfectly well, with one suggestion- use clear hose. You will be able to see any emulsion that builds up if you ride in wet weather.
To combat this, I cut a clear lid from an aerosol can to fit over the filter and keep it from road spray.

Ideally you fit a catch tank tee piece at the lowest point, but that's probably overkill.

However, you won't get a sudden increase in power; it just makes cleaning up the pipework from the airbox possible, and means that you can regain the corners, as you don't need corner filters.
Just wrap a section of air filter foam over the stubs and clip them on with a cable tie, and the job is a good one, matey.

As to mine- I've been working on it every night this week- should be done by the weekend, I hope. I had to cut and re-glass some sections to allow the tank to sit down far enough- I may have got a bit greedy in trying to maximise the volume...
Funnily enough it doesn't look anywhere near as big once you get the carbs in.....
When it's ready for final assembly I'll do a series of build pix.

Thanks. Im not expecting any power, just to get the airbox cleaned up. I may put in a drain hose if I go that way.

[lloydie]

I ran a gutted air box for a year with external filters and found even with them covered up like tony says they get blocked so as long as you clean them there fine .
Just treat them as a serviceable item and all is good

[NZSpokes]

I ran a gutted air box for a year with external filters and found even with them covered up like tony says they get blocked so as long as you clean them there fine .
Just treat them as a serviceable item and all is good

Filters for the carb diaphragm you mean?

At this stage they will remain stock as I just want the oil breather out. But will do the diaphragm ones a bit later on with more mods.

[lloydie]

No the oil breather pod filters . The diaphragm ones were fine after 15k

[NZSpokes]

No the oil breather pod filters . The diaphragm ones were fine after 15k

Problem is more where to put the filters i would have thought.

[tony.mon]

Latest:

All fitted and connected- runs like sh1t, as anticipated. Rear cylinder is fuelling an 19:1 and over, with A 178 fitted, so I'll play with a bigger main tomorrow evening and see if I can get it into range.
A few progress pics:

Untidy cables, pipes and tubes-

Slightly tidier-


Lashed down and sealed up:


The Flo Commander seems to make a difference, though, so with a little luck I will be able to get main jets sorted a lot quicker this time.

[lloydie]

Nice progress tony

[tony.mon]

So, got it fired up today with the fibreglass airbox on, with the carbs set the same as they were with the previous modified airbox.
It ran ok at lower revs, up to 3500, but over that I could see from the lambda readouts I have that the rear cylinder was running very lean- around 18 or 19:1. Front was slightly lean, at 14:1 or so.
That turned out to be the rear carb not seated properly on its rubber mounting- with the airbox now surrounding the carbs you can't see whether it's sitting squarely or not.

Once that was sorted, it was still running lean, around 14:1 front and 15.5:1 rear.

It's so much easier with the Lambda readouts on the dash- otherwise I wouldn't know which one was running lean, or whether one was rich and the other lean- a single probe down the exhaust wouldn't be able to tell what was going on, because the gases mix together in the collector before going to the cans.

I pulled the carbs out once more- it takes longer with the surrounding style of airbox, around a couple of hours each time.
Jets were, with the previous airbox, 172 front and 178 rear.
I changed them to richer ones, 175 front and 182 rear, and left the other settings alone- needles in the centre position, 45 pilots fitted, fuel screws 2 turns out on both.

Now we managed to get to 13.5:1 front, and 14:1 rear- near enough for a road test, I thought.
So on with the gear, off down the road- it was rough- getting leaner the higher the revs went.

But I've fitted a Flo-Commander as part of this project, and so tried adjusting from the recommended centre setting of three turns out. One turn in (richer) made it run a little cleaner, and it now pulled well at the top end, but still misfired mid-range.
Another turn in, and wonders will never cease- not far off, and running cleanly.

Happy days!
I tried turning it fully in, and this made it too rich, and with a bit of experimentation it's now half a turn out from fully in.
This means that it is still needing larger jets, so I'll try going to 178 front and 188 rear- I think that's likely to get me to a happily running bike with the Flo-Commander set to around three turns out.

I might carry on playing with needle heights one clip at a time, to try to get it perfect, but tbh I will be happy enough with it as it is at the moment for now, well, happy enough to get the next dyno run done one morning this coming week, anyway.
It feels strong, but then I haven't been able to ride it for three weeks, so it's hard to be objective. It wheelies alright, though, especially accelerating from banked over- it's always a nice feeling to have the front lifting when still on its side....


Next I'll sort the link sections for the ram air and hook that up, but that might have to wait, because I want to have the high comp pistons and reground cams in again in time for the Wales meet.
Fitting those should be easy enough, I can leave the motor in the frame, take the heads off and hone, wash through, fit pistons and reassemble, swapping cams, re-timing, re-shimming, etc - I'll probably take a day off to make a long weekend of it, no point rushing.
The choke knob now pokes out under the LH side tank cutout, and the gland covering the adjuster position for the Flo-Commander is in the RH cutout- might as well make use of them, I thought.

I'm happy enough with the way it's running to give it a little rinse, so pics of the sort-of finished job will be along later this evening.
Sounds nice and throaty when accelerating, too.

There are some negatives to this; pulling the carbs off to change jets now takes half an hour longer, and is more fiddly. You can't adjust tickover speed or fuel screws from the outside any more- tickover speed can be done with the airbox lid off, but the carbs have to be removed to get to the fuel screws underneath.

This glassfibre airbox project started before Christmas.....

If I were to do this again I would be sorely tempted to buy the glassfibre one from Sebimoto- I know quality, based on AP's tail cover may not be great, but it would have been a lot quicker to modify that than create my own.
If it fitted perfectly and worked, sealing up to the underside of the tank etc, I'd be tempted to pay the extra and get the Carbon one.
When trying to make mine, and get it to seal against the underside of the tank, I found it much more difficult than first thought- I even bought a scrap tank and cut the base off, to ensure a good fit, but still wasn't happy with the seal- that's why I ended up joining the top of a spare airbox on to get the one I have ended up with.

Ah well, best get washing, I suppose- it'll take me a while as I haven't had much practise...

[Kev L]

Interesting project Tony and a really clear write up as well. Cheers.
I admire your persistence getting it to fuel as well as you have.

[tony.mon]

Pics as promised:


You can see the relocated choke here:


There's a blanking bolt screwing into a piece of threaded plastic rod in the gland- just unscrew the bolt and I can get a screwdriver onto the adjuster for the Flo-Commander.
I'm really impressed with the F-C- it's simple, easy to fit, and works really well.

[lloydie]

Very interesting tony keep up the hard work

[tony.mon]

Very interesting tony keep up the hard work

No.
I'm knackered, and need a break, so I'm off on holiday after this week at werrrrk.
I think I'll leave it alone for a bit (after the dyno run) and let a bit more enthusiasm build up.

As I said, I'll get the hone, pistons and cams in and then take it to the Wales meet to see how it stacks up.

Seems like I'm spending twenty large on a conservatory touch-up and re-roof, so won't have any cash for mods much after that.

I've bloody cleaned it, what more do you want from me?

[lloydie]

polish and wax ha ha

[fabiostar]

serious amount of work sir but a great read i have to say.